Wynne Parry LiveScience.com Yahoo News 26 Jun 11;
A single-celled alga that went extinct in the North Atlantic Ocean about 800,000 years ago has returned after drifting from the Pacific through the Arctic thanks to melting polar ice. And while its appearance marks the first trans-Arctic migration in modern times, scientists say it signals something potentially bigger.
"It is an indicator of rapid change and what might come if the Arctic continues to melt," said Chris Reid, a professor of oceanography at the Sir Alister Hardy Foundation for Ocean Science in the United Kingdom.
Arctic sea ice has been in decline for roughly three decades, and in several more recent summers, a passage has opened up between the Pacific and Atlantic. In as little as 30 years, Arctic summers are projected to become nearly ice free. [Earth in the Balance: 7 Crucial Tipping Points]
The findings, first reported in 2007, are among the 300 European Union-funded research papers being synthesized by a collaborative project dubbed CLAMER for Climate Change & European Marine Ecosystem Research. All of this work explores the effects of climate change on marine environments, documenting evidence of major transitions under way in the waters around Europe and the North Atlantic.
Many shifts
The alga, called Neodenticula seminae, belongs to a group of organisms with glasslike walls known as diatoms. The diatom is not the only living thing that may have taken advantage of retreating Arctic sea ice to travel.
In 2010, a gray whale appeared in the Mediterranean Sea. This species was thought to be confined to the Pacific Ocean, disappearing from the North Atlantic in the 1700s. This whale's voyage was most likely made possible by shrinking Arctic sea ice, concluded researchers writing in the journal Marine Biodiversity Research.
Work compiled so far by CLAMER contains evidence of many changes within European waters. Species are moving northward — for example, fish diversity is increasing in the North Sea as it warms. Warming water is also causing problems by interfering with organisms' timing. For instance, Baltic clam spawning is timed to allow larvae to take advantage of the bloom in tiny plants while avoiding predatory juvenile shrimp. However, warming water interferes with this sequence and hurts the clam's reproduction. Yet other research documented shifts in the population of copepods, tiny crustaceans, with potentially serious consequences for fisheries, including cod, which depend on the critters for food.
"The major thing about this climate change is the rate at which things are happening at this moment. … We had change, we had warming, we had cooling, we had ice ages, but it was always slower than things are going now," said Katja Philippart, a marine biologist with the Royal Netherlands Institute for Sea Research and a coordinator for CLAMER. "The rate is unprecedented."
Life in the modern seas faces added stresses — pollution, habitat loss, acidification and heavy fishing — that did not exist during prior shifts in climate not caused by humans, Philippart said.
No welcome back
The diatom that Reid and colleagues discovered in the North Atlantic disappeared from this part of the globe long ago, according to evidence found in sediment on the seafloor, Reid said.
Until recently, it remained in the more favorable conditions of the Pacific Ocean before reappearing in large numbers in a plankton survey in May 1999 in the Labrador Sea. The diatom most likely traversed the Arctic thanks to melting sea ice, according to Reid and colleagues.
Declining Arctic sea ice reached a milestone in the summer of 1998 when the ice pulled back completely from the Arctic coasts of Alaska and Canada, opening up the Northwest passage through which the diatom may have passed, Reid and colleagues write in their report of the diatom's return published in the journal Global Change Biology in 2007.
"The diatom could act in competition with other species of diatoms or other species of algae (and) could theoretically lead to the extinctions, but I think that is highly unlikely," Reid told LiveScience.
Like most introduced or returning species, it will likely settle into a niche, he said.
However, its arrival is likely a precursor to others, such as fish from the Pacific, with potentially greater impacts on life in the North Atlantic, he said.
"Because of the unusual nature of the event, it appears that a threshold has been passed, marking a change in the circulation between the North Pacific and the North Atlantic Oceans via the Arctic," Reid and colleagues concluded in 2007.
CLAMER's work is scheduled to conclude withan international conference at the Royal Flemish Academy of Belgium, Sept. 14-15.
Whales, plankton migrate across Northwest Passage
Arthur Max Associated Press Yahoo News 26 Jun 11;
AMSTERDAM – When a 43-foot (13-meter) gray whale was spotted off the Israeli town of Herzliya last year, scientists came to a startling conclusion: it must have wandered across the normally icebound route above Canada, where warm weather had briefly opened a clear channel three years earlier.
On a microscopic level, scientists also have found plankton in the North Atlantic where it had not existed for at least 800,000 years.
The whale's odyssey and the surprising appearance of the plankton indicates a migration of species through the Northwest Passage, a worrying sign of how global warming is affecting animals and plants in the oceans as well as on land.
"The implications are enormous. It's a threshold that has been crossed," said Philip C. Reid, of the Alister Hardy Foundation for Ocean Science in Plymouth, England.
"It's an indication of the speed of change that is taking place in our world in the present day because of climate change," he said in a telephone interview Friday.
Reid said the last time the world witnessed such a major incursion from the Pacific was 2 million years ago, which had "a huge impact on the North Atlantic," driving some species to extinction as the newcomers dominated the competition for food.
Reid's study of plankton and the research on the whale, co-authored by Aviad Scheinin of the Israel Marine Mammal Research and Assistance Center, are among nearly 300 scientific papers written over the last 13 years that are being synthesized and published this year by Project Clamer, a collaboration of 17 institutes on climate change and the oceans.
Changes in the oceans' chemistry and temperature could have implications for fisheries, as species migrate northward to cooler waters, said Katja Philippart, of the Royal Netherlands Institute of Sea Research who is coordinating the project funded by the European Union.
"We try to put the information on the table for people who have to make decisions. We don't say whether it's bad or good. We say there is a high potential for change," she said.
The Northwest Passage, the route through the frigid archipelago from Alaska across northern Canada, has been ice-free from one end to the other only twice in recorded history, in 1998 and 2007. But the ice pack is retreating farther and more frequently during the summers.
Plankton that had previously been found only in Atlantic sea bed cores from 800,000 years ago appeared in the Labrador Sea in 1999 — and then in massive numbers in the Gulf of St. Lawrence two years later. Now it has established itself as far south as the New York coast, Reid said.
The highly endangered gray whale sighted off the Israeli coast in May 2010 belonged to a species that was hunted to extinction in the Atlantic by the mid-1700s. The same animal — identified by unique markings on its fluke, or tail fin — appeared off the Spanish coast 22 days later, and has not been reported seen since.
Though it was difficult to draw conclusions from one whale, the researchers said its presence in the Mediterranean "coincides with a shrinking of Arctic Sea ice due to climate change and suggests that climate change may allow gray whales to re-colonize the North Atlantic."
That may be good for the whales, but other aspects of the ice melt could be harmful to the oceans' biosystems, the scientists warn.
Plankton is normally the bottom of the marine food chain, but some are more nutritious than others. Plankton changes have been blamed for the collapse of some fish stocks and threats to fish-eating birds in the North Sea, the studies show.
The migration of a solitary whale and two species of plankton is not of much concern so far, Reid said. "It's the potential for further ones to come through if the Arctic opens. That's the key message."
